Lodgepole pine beetle, Dendroctonus murryanae,
 

Fig. 98 Lodgepole pine beetle larvae. Note the anal shields.	Fig. 99 Lodgepole pine beetle crystallized pitch tubes on the lower bole of an attacked tree (note: red frass is from Ips pini, D. murrayane produces no such frass).	Fig. 100 Lodgepole pine beetle egg gallery (Arrow) with brood chamber on its lower side, created by newly hatched larvae. The larvae expand the chamber as they grow in size and do not mine separately.
Fig. 100a Lodgepole pine beetle eggs laid in a strung out mass at a widened place along one side of the egg gallery.

Tree Species Attacked: Stressed or damaged usually mature lodgepole pine.

Insect Description & Damage Symptoms: The adult beetle is 4.5 to 6.9 mm long, dark brown to black, with reddish-brown wing covers. Two separated dorsal plates are present on the posterior of larvae.  One generation occurs per year. Susceptible standing trees are old, injured, or stressed; fresh stumps and windfalls may also be infested. Usually, only one to five attacks occur per tree, located within 20 cm of the ground. The sparse attacks stimulate formation of large pitch masses at the gallery entrances. The resin composing these masses crystallizes, eventually forming bleached granules that accumulate on the ground below. The adult females construct egg galleries that are irregularly linear and vary from nearly vertical to horizontal, averaging about 18 cm in length. One clutch of eggs is laid per gallery, in an elongate mass, always on the downward side. Hatched larvae aggregate along a feeding front, forming a chamber that expands as the larvae grow in size.

Damage: This beetle is not a primary tree killer. Unlike the mountain pine beetle, which mass attacks as adults, it aggregates in the larval stage and attacks at low density. In B.C., however, it has been reported to kill old lodgepole pine left standing after timber harvesting. .

Similar Damage: Pitch masses and galleries may be confused with the red turpentine beetle, Dendroctonus valens. Larvae of the latter, however, have the dorsal plates fused; those of D. murrayanae are separate. The mountain pine beetle seldom occurs in trees with D. murrayanae.

(text and figures updated by Malcolm Furniss, November 2009)

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BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated November 12, 2009